The projector is a common optoelectronic display device and is widely applied in several occasions such as the life entertainment, the academic lecture, the business show. According to the principles of displaying, the projecting system includes a cathode-ray tube (CRT) display device, a liquid crystal display (LCD), a digital light processing (DLP) projecting device, and a liquid crystal on silicon (LCoS) projecting device, in which the DLP projecting device enjoys customers' high praise and shares the major market about the projecting system products because of the advantages of the DLP projecting device such as the high luminance, the high chromatic fidelity, the high response efficiency, and the compact configuration.
The DLP projecting device usually has a digital micro-mirror device (DMD) to modulate the light and passes an image through the projecting lens to project the image on the screen, in which the single-chip DLP projector and the double-chips DLP projector both have color wheels to separate the colors of the light to form color displaying images. In the preferred condition, the image projected by the projector may have a wide color gamut, a high brightness, and an ideal white balance because of the color wheel of the projector.
The conventional color wheel includes a plate and a phosphor layer disposed on the plate. The phosphor layer has a shining light area and the shining light area may be extended when the plate rotates. Simultaneously, the phosphor layer of the color wheel may be stained with the dust to cause the optical efficiency decreased. Therefore, the color wheel must be disposed in an enclosed cavity to prevent from the entering of the dust. However, owing to the needing of the high brightness, the projector has a high energy light source such that the temperature of the cavity may be increased to cause the optical efficiency of the phosphor layer being decreased and the gel for adhering the phosphor layer on the plate may be burned when the phosphor layer is disposed in an over-high temperature.
Recently, some patents are descript to be configured to decrease the temperature of the color wheel when the plate of the color wheel rotates such as U.S. Pat. No. 7,018,051 and US publication number 20130169938. However, the mentioned patents are descript that several holes or extra structures are disposed on the plates such that the air rapidly follows to accelerate the heat dissipation of the plate, but the configuration of the plate is dramatically changed to cause the rotatable plate having an unstable dynamic balance. In addition, the heat dissipating region of the plate may be decreased because the plate has several holes. Furthermore, the manufacture of the plate may need many complex processes.